Sieve tray for a sieve device

ABSTRACT

A sieve tray produced of a wire netting, in the case of which the warp and weft wires are mutually connected in a weave, is to be designed such that particles of a certain size can be sieved out of a material, particularly out of an emulsion.  
     According to the invention, the sieve netting ( 11 ) is provided with mutually spaced alternating crossings ( 16  which extend diagonally with respect to the warp and weft wires and in a zigzag shape, each straight-line section extending over a constant number of warp wires ( 14 ). However, each straight-line section of each alternating crossing ( 16 ) is to extend maximally over 20 warp wires.  
     The sieve tray according to the invention is particularly suitable for sieve devices.

[0001] The invention relates to a sieve tray for a sieve device which has at least one sieve netting consisting of a wire netting, and in which each wire netting contains warp and weft wires mutually connected by a weave.

[0002] The concerned sieve trays are known in many constructions. In the normal case, each sieve tray consists of the upper sieve netting—relative to the installed position—and of a supporting netting situated below which has a larger mesh size. The mesh sizes of the sieve nettings depend on the sizes of the particles to be sieved. The sieve trays normally have a round or square design. Frequently, the sieve trays are also provided with tensioning edges in order to tension the sieve netting either transversely to the flow direction of the material or in the longitudinal direction of the material. The so-called tensioning edges are also known in various constructions. In order to separate particles from a material or a liquid, an emulsion, or the like, two different methods are known, specifically the sieving by means of a sieve device or the filtering by means of a filter device. For the sieving, the above-mentioned sieve tray is used which, by means of a vibration generator, is caused to carry out a swinging motion.

[0003] In the case of the previously used sieve trays, the wire netting consists exclusively of the warp wires and the weft wires which extend at a right angle thereto. As a result, square meshes or openings are created in the projection. Such sieve trays have been very successful but are not completely satisfactory for certain applications, such as the sieving of particles of a certain size from an emulsion.

[0004] It is an object of the invention to design a sieve tray of the initially described type in such a manner that particles of a certain size can be sieved out of a material, particularly out a liquid, an emulsion or the like.

[0005] This object is achieved in that the sieve netting is provided with mutually spaced alternating crossings situated diagonally to the warp and weft wires.

[0006] The size of the meshes is now no longer determined by the spaces between the warp and weft wires but gores are formed which are no longer square. The size is therefore also a function of the positions of the alternating crossings with respect to the warp and weft wires. The warp and weft wires are expediently in contact with one another in a twill-lace weave. The alternating crossings additionally contribute to the stabilization of the sieve netting because they also consist of wires.

[0007] In a preferred embodiment, the alternating crossings extend in a zigzag shape from one edge to the opposite edge. The alternating crossings expediently extend from the edges which extend parallel and at a distance from the warp wires. The zigzag-shaped course of the alternating crossings additionally increases the stability, so that it can be assumed that the service life of a sieve tray can be extended. So that a uniform mesh size is achieved over the entire sieve surface, it is provided that each straight-lined section of the alternating crossings extends over a constant number of warp wires. In a special case, in which the warp wires and the weft wires are situated at equal mutual distances and therefore form square meshes, it is provided that the straight-lined sections of the alternating crossings also extend over the same number of weft wires as in the case of warp wires. The individual straight-lined sections of the alternating crossings will then be situated at an angle of 45° with respect to the warp and weft wires. In an embodiment, it is provided that the straight-lined sections of the alternating weft wires maximally extend over 20 warp wires.

[0008] In a further development, it is provided that the weaves of the warp and weft wires are special zz-weaves. As a result, favorable conditions are obtained for the weaves of the alternating crossings. It is provided in an embodiment that a side change of the warp wires takes place when they have skipped a certain number of weft wires, and this number corresponds to the warp wires skipped by the weft wires. In an embodiment, the number of skipped warp wires amounts to two. The respective sections of the warp and the weft threads situated on one side are offset from one warp wire to the next warp wire by one weft wire. The sections of the weft wires situated on one side are also offset with respect to one another by one warp wire from one weft wire to the next.

[0009] Depending on the construction, the diameters of the warp wires 14 and the weft wires 15 may coincide or approximately coincide, but may also be different. The diameters of the alternating crossings may coincide with the diameters of the warp wires and, if the diameters of the weft wires deviate therefrom, may also coincide with the diameters of the weft wires or approximately coincide. However, constructions are also conceivable in which the diameters of the alternating crossings deviate from the diameters of the warp wires as well as of the weft wires. Depending on the application purpose, a supporting netting also can be functionally assigned to the sieve netting. The mesh width of this supporting netting is normally larger than that of the sieve netting.

[0010] The concerned sieve trays are considered to be fine-meshed. So that a uniform tension is ensured along the entire width or the entire length, it is provided that the sieve tray is equipped with one tensioning edge respectively on two mutually opposite sides, which tensioning edge is formed by shaping. As an alternative, the sieve netting may also be clamped onto a frame. For compensating tension differences in the sieve netting, a flexible element, preferably a plastic element, may be worked into at least one tensioning edge.

[0011] The invention will be explained in detail by means of the attached drawings.

[0012]FIG. 1 is a perspective view of a sieve tray;

[0013]FIG. 2 is a top view of the wire netting of the sieve tray;

[0014]FIG. 3 is a sectional view of a weft wire of the wire netting according to FIG. 2;

[0015] FIGS. 4 to 6 are dobby cards in three different implementations.

[0016]FIG. 1 illustrates a possible embodiment of the sieve tray 10 according to the invention whose sieve netting 11 will be explained in greater detail by means of FIGS. 2 to 6. On two mutually opposite sides, the sieve tray 10 is provided with one tensioning edge 12,13 respectively which, in the illustrated embodiment, have a U-shaped and mutually facing design. The free end areas of the tensioning edges 12, 13 are bent in the opposite direction and contact the assigned areas of the U-shaped part. Optionally, additional flexible plastic elements can be worked into the tensioning edge in order to absorb tension differences in the sieve netting. According to FIG. 1, the tensioning edges 12, 13 are provided on the shorter sides. In contrast to this construction, they may also be shaped onto the longer sides.

[0017]FIG. 2 shows the starting product of the sieve netting 11 which is formed of warp wires 14 and of weft wires 15 and in which the warp wires 14 and the weft wires 15 are interwoven in a special zz-weave. The wire netting illustrated in FIG. 2 is considered to be an example. In this construction, the warp threads 14 and the weft threads 15 are arranged at the same mutual spacing so that square meshes 17 are obtained. In the embodiment according to FIG. 2, the side change of the warp thread 14 takes place when the warp threads have skipped two weft threads 15. The side change of the weft threads 15 takes place in the same manner; that is, when two warp threads 14 have been skipped. FIG. 2 also shows that the side change of the warp threads 14 and of the weft threads 15 of two successive wires is in each case offset by one wire.

[0018] In the manner of examples, FIGS. 4 to 6 show that the wire netting according to FIG. 2 is equipped with alternating crossings 16 situated diagonally with respect to the warp wires 14 and the weft wires 15. In the illustrated embodiments, the alternating crossings 16 extend at an angle of 45° with respect to the warp wires and to the weft wires 15. The spacing of the alternating crossings 16 in the illustrated embodiments amounts to two warp wires 14 and two weft wires 15 respectively. As a result, a fishbone-type pattern of the sieve netting 11 is obtained. FIGS. 4 to 6 show that the alternating crossings 16 extend in a zigzag shape. Each straight-line area to the change maximally skips 20 warp threads 14. In the illustrated embodiment, the alternating crossings 16 have the same diameter as the warp wires 14 and the weft wires 15. However, mutually deviating diameters are also conceivable.

[0019] The invention is not limited to the illustrated embodiments. It is essential that, for influencing the sizes of the meshes, the sieve netting 11 is equipped with alternating crossings 16 extending diagonally to the warp wires 14 and the weft wires 15. 

1. Sieve tray for a sieve device which has at least one sieve netting consisting of a wire netting, and in which each wire netting contains warp and weft wires mutually connected in a weave, characterized in that the sieve netting (11) is provided with mutually spaced alternating crossings (16) extending diagonally with respect to the warp and weft wires (14, 15).
 2. Sieve tray according to claim 1, characterized in that the alternating crossings (16) extend in a zigzag shape, each straight-line section extending over a constant number of warp wires (14).
 3. Sieve tray according to claim 2, characterized in that each straight-line section of each alternating crossing (16) extends maximally over 20 warp wires (14).
 4. Sieve tray according to one or several of the preceding claims 1 to 3, characterized in that the weave of the warp and weft wires (14, 15) is a special zz-weave.
 5. Sieve tray according to one or several of the preceding claims 1 to 4, characterized in that the side change of the warp wires (14) and of the weft wires (15) takes place after the skipping of a preferably constant number of wires.
 6. Sieve tray according to one or several of the preceding claims 1 to 5, characterized in that the diameters of the warp wires (14) and of the weft wires (15) coincide or approximately coincide.
 7. Sieve tray according to one or several of the preceding claims 1 to 5, characterized in that the diameters of the warp wires (14) and of the weft wires (15) differ.
 8. Sieve tray according to one or several of the preceding claims 1 to 7, characterized in that the alternating crossings extend at an angle of 45° with respect to the warp wires (14) and the weft wires (15).
 9. Sieve tray according to one or several of the preceding claims 1 to 8, characterized in that the sieve tray (10) is provided on two mutually opposite sides with tensioning edges (12, 13) formed by shaping or the sieve netting is clamped onto a frame.
 10. Sieve tray according to claim 8, characterized in that, for the absorption of tension differences of the sieve netting, additional flexible elements, preferably plastic elements, are worked into at least one tensioning edge.
 11. Sieve tray according to one or several of the preceding claims 1 to 10, characterized in that the sieve bottom has a supporting netting assigned to the sieve netting. 